1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method of the semiconductor device, and particularly is preferable for application in a field-effect transistor reduced to a submicron order or less.
2. Description of the Related Art
In the field-effect transistors of recent years, gate lengths are shortened to a submicron order to promote densification and speedup of semiconductor integrated circuits. In order to suppress increase in resistance of source/drain layers of miniaturized field-effect transistors, silicidation of surfaces of the source/drain layers is performed.
For example, JP-A-2002-110991 (hereinafter referred to as Patent Document 1) discloses a method for forming a joint interface of a diffusion layer which is a silicon portion of an SOI layer and a metal silicide layer to be a (111) silicon plane in order to reduce junction leakage of the metal silicide layer.
However, when the gate length of a field-effect transistor is reduced to about 100 nm or less, the control power of channel potential by a gate electrode reduces, and a leakage current flowing between a source and a drain increases. Therefore, in the field-effect transistor in which the gate length is reduced to about 100 nm or less, it becomes difficult to suppress a short channel effect sufficiently, thus causing the problem that a leakage current in an off state of the field-effect transistor increases.
Further, in the method of siliciding the surfaces of the source/drain layer, when the silicide layer reaches the joint surfaces of the source/drain layer and the channel region, junction leakage is caused, and therefore, it is necessary to make the silicide layer thin, thus causing the problem of making it difficult to contribute to reduction in resistance of the source/drain layer sufficiently.
In the method disclosed in Patent Document 1, there is the problem that when the silicide layer reaches the area in the vicinity of the joint surfaces of the source/drain layer and the channel region, and when the silicide reaction proceeds beyond the joint surfaces of the source/drain layer and the channel region, junction leakage is caused.